Diagonal strut device, method for manufacturing same and motor vehicle underfloor reinforced by means of diagonal structure device

Abstract

A diagonal strut device ( 1 ) for reinforcing arrangement on an undercarriage of a motor vehicle. The diagonal strut device ( 1 ) has a plurality of struts ( 2 ) made from a fibet-reinforced plastic composite material, which extend away from a central joint element ( 3 ). Each strut ( 2 ) can be connected to the undercarriage via it's end facing away from the central joint element ( 3 ). For this, a connecting joint element ( 4 ) is arranged on the end of each strut ( 2 ) facing away from the central joint element ( 3 ). The central joint element ( 3 ) and the connecting joint elements ( 4 ) are formed from a light metal material. The central joint element ( 3 ) and the connecting joint elements ( 4 ) are then connected to the struts ( 2 ) by an at least firmly bonded cast joint. Further, a method for the production of a diagonal strut device ( 1 ), as well as a motor vehicle undercarriage, which uses the diagonal strut device ( 1 ) for reinforcement.

The invention claimed is: 
     
       1. A diagonal strut device ( 1 ) for reinforcing arrangement on an undercarriage of a motor vehicle, wherein the diagonal strut device ( 1 ) comprises:
 a central joint element ( 3 ), 
 a plurality of struts ( 2 ) made from a fibre-reinforced plastic composite material, which extend away from the central joint element ( 3 ), wherein each strut ( 2 ) has an end facing the central joint element and an end facing away from the central joint element, and can be connected to the undercarriage via the end facing away from the central joint element ( 3 ), and a connecting joint element ( 4 ) arranged on the end of each strut ( 2 ) facing away from the central joint element ( 3 ) to provide the connection to the undercarriage, 
 wherein the central joint element ( 3 ) and the connecting joint elements ( 4 ) are formed from a light metal material and are connected to the struts ( 2 ) by an at least firmly-bonded cast joint. 
 
     
     
       2. The diagonal strut device ( 1 ) according to  claim 1 , wherein at least one of the central joint element ( 3 ) and the connecting joint elements ( 4 ) are cast into the end sections of the struts ( 2 ). 
     
     
       3. The diagonal strut device ( 1 ) according to  claim 1 , wherein the end sections of the struts ( 2 ) are moulded into the central joint element ( 3 ) or the connecting joint elements ( 4 ). 
     
     
       4. The diagonal strut device ( 1 ) according to  claim 1 , the struts ( 2 ) have a hollow profile at least at the end sections, into which at least one of the central joint element ( 3 ) and the connecting joint element ( 4 ) is moulded. 
     
     
       5. The diagonal strut device ( 1 ) according to  claim 1 , wherein the struts ( 2 ) have openings or structures or both at their end sections, which are permeated or enclosed positively by the cast material of the cast joint. 
     
     
       6. The diagonal strut device ( 1 ) according to  claim 1 , wherein the struts ( 2 ) have at least one of a thermally insulating coating and a metallic coating added to them at least at their end sections at which the cast joint is provided. 
     
     
       7. The diagonal strut device ( 1 ) according to  claim 1 , wherein the struts ( 2 ) have an adhesion-improving coating added to them at least at their end sections at which the cast joint is provided. 
     
     
       8. The diagonal strut device ( 1 ) according to  claim 1 , wherein the struts ( 2 ) have an adhesion-improving coating added to them at least at their end sections at which the cast joint is provided, which provides a structured surface. 
     
     
       9. The diagonal strut device ( 1 ) according to  claim 1 , wherein the diagonal strut device ( 1 ) comprises connecting aids, by means of which the diagonal strut device ( 1 ) can be connected to the undercarriage, wherein the connecting aids are provided on the connecting joint elements ( 4 ) and comprise at least one of bore-holes, inserts, screw threads, adherends, clinch elements and weld contact areas. 
     
     
       10. The diagonal strut device ( 1 ) according to  claim 1 , wherein the central joint element ( 3 ) and or the connecting joint elements ( 4 ) are additionally connected to the struts ( 2 ) by a force-fit connection. 
     
     
       11. The diagonal strut device ( 1 ) according to  claim 1 , wherein the central joint element ( 3 ) and or the connecting joint elements ( 4 ) are additionally connected to the struts ( 2 ) by riveting or screwing ( 5 ). 
     
     
       12. The diagonal strut device ( 1 ) according to  claim 1 , wherein the struts ( 2 ) are fibre-reinforced plastic pultrusion profiles ( 2 ). 
     
     
       13. The diagonal strut device ( 1 ) according to  claim 1 , wherein the struts ( 2 ) are fibre-reinforced plastic pultrusion profiles ( 2 ) having a fibre proportion of up to 70% with respect to the total weight of the fibre-reinforced plastic pultrusion profile ( 2 ). 
     
     
       14. The diagonal strut device ( 1 ) according to  claim 1 , wherein the diagonal strut device ( 1 ) comprises up to four struts ( 2 ), which are arranged in an X-shape on the central joint element ( 3 ), such that the central joint element ( 3 ) is separated from a plane that fixes the fastening element ( 4 ). 
     
     
       15. The diagonal strut device ( 1 ) according to  claim 1 , wherein the diagonal strut device ( 1 ) comprises up to four struts ( 2 ), which are arranged slanted towards one another at the central joint element ( 3 ), such that the central joint element ( 3 ) is separated from a plane that fixes the fastening element ( 4 ). 
     
     
       16. The diagonal strut device ( 1 ) according  claim 1 , wherein the light metal material is a light metal or a light metal alloy. 
     
     
       17. A method for the production of a diagonal strut device ( 1 ) according to  claim 1 , comprising the following steps:
 providing the plurality of struts ( 2 ) made from a fibre-reinforced plastic composite material and inserting them into a die-casting tool, wherein the struts ( 2 ) are located close to one another with a first end section in a region provided for the formation of the central joint element ( 3 ) in one cavity and, with their second end sections, are located separated from one another in a respective region in a cavity, which is provided for the formation of the connecting joint element, 
 closing the die-casting tool and die-casting a molten light metal material into the cavities, forming the central joint element ( 3 ) and connecting joint elements ( 4 ) and simultaneously firmly bonding the central joint element ( 3 ) and the connecting joint elements ( 4 ) to the struts ( 2 ), and 
 removing the diagonal strut device ( 1 ). 
 
     
     
       18. The method according to  claim 17 , comprising the following step:
 during the die-casting, removing heat from the die-casting tool by means of a cooling system for the die-casting tool. 
 
     
     
       19. A motor vehicle undercarriage, which is reinforced by a diagonal strut device arranged on the motor vehicle undercarriage, wherein the diagonal strut device comprises:
 a central joint element ( 3 ), 
 a plurality of struts ( 2 ) made from a fibre-reinforced plastic composite material, which extend away from a central joint element ( 3 ), wherein each strut ( 2 ) has an end facing the central joint element and an end facing away from the central joint element, and is connected to the undercarriage via the ends facing away from the central joint element ( 3 ), and 
 a connecting joint element ( 4 ) arranged on the end of each strut ( 2 ) facing away from the central joint element ( 3 ) connection with the undercarriage unreleasably, wherein the central joint element ( 3 ) and the connecting joint elements ( 4 ) are formed from a light metal material and are connected to the struts ( 2 ) by an at least firmly-bonded cast joint.